Development Voltage Polarity Control for Toner Adhesion Prevention
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Solution Overview
Problem
In electrophotographic image forming apparatuses, there is a challenge in preventing toner from unintentionally adhering to the photosensitive drum during the initial rotation phase before the development voltage reaches the target voltage, leading to potential image defects on the back surface of sheets.
Innovation Solution
A power supply apparatus is designed with a boost circuit and a control system that adjusts the development voltage by switching the polarity of the output voltage using a boost circuit and transistors, ensuring the voltage is sufficiently high to inhibit toner adhesion during the initial rotation phase and maintaining appropriate voltages during image formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the photosensitive drum starts rotating before the development voltage reaches the target voltage, then the drum can rotate stably at constant speed, but toner unintentionally adheres to the photosensitive drum from the developing roller
Solution Approach 1:
The invention applies preliminary anti-action by setting the development voltage to a specific value during the initial rotation phase before image formation. This preliminary voltage setting prevents toner from adhering to the photosensitive drum while the drum is stabilizing its rotation, thereby counteracting the potential harmful effect of unintended toner adhesion before the actual imaging process begins.
Solution Approach 2:
The invention implements dynamics by dynamically adjusting the development voltage based on the operational phase. During the initial rotation phase, a different voltage is applied compared to the image formation phase. This dynamic voltage adjustment allows the system to adapt to the changing conditions of drum rotation stability while preventing toner adhesion issues.
2Object-generated harmful factors
If the development voltage is increased to prevent toner adhesion, then toner adhesion is inhibited, but the voltage may cause other issues during image formation
Solution Approach 1:
The invention applies dynamics by dynamically changing the development voltage based on the operational phase. During initial rotation, a higher voltage is applied to prevent toner adhesion. During image formation, the voltage is adjusted to appropriate levels to ensure reliable image formation. This dynamic adjustment resolves the contradiction between preventing toner adhesion and maintaining image formation reliability.
Solution Approach 2:
The invention uses preliminary action by setting the development voltage to a specific preventive value during the initial rotation phase before image formation begins. This preliminary voltage setting prevents toner adhesion issues from occurring in the first place, allowing subsequent image formation to proceed with normal voltage settings without experiencing adhesion problems.
3Stability of the object's composition
If a waiting time is provided for the photosensitive drum to rotate stably, then rotational stability is achieved, but image formation is delayed
Solution Approach 1:
The invention implements continuity of useful action by maintaining the development voltage at an appropriate level throughout both the initial rotation phase and the image formation phase, without interrupting or stopping the process. This continuous voltage application allows the drum to stabilize while still maintaining conditions ready for immediate image formation, eliminating idle waiting time.
Solution Approach 2:
The invention applies preliminary action by setting the development voltage during the initial rotation phase to prepare the system for immediate image formation. This preliminary voltage setting ensures that when the drum reaches stable rotation, the voltage is already at the appropriate level for image formation, eliminating the need for additional waiting time or voltage adjustment delays.
4Object-generated harmful factors
If the voltage polarity is switched to inhibit toner adhesion, then toner adhesion is prevented, but the circuit complexity increases
Solution Approach 1:
The invention applies parameter changes by modifying the voltage polarity parameter during different operational phases. During initial rotation, the voltage polarity is set to inhibit toner adhesion. During image formation, the polarity is adjusted to appropriate levels. This parameter-based control achieves toner adhesion prevention without requiring complex additional hardware, as it utilizes existing voltage control capabilities.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively prevents toner adhesion to the photosensitive drum during initial rotation and ensures accurate image transfer, reducing the likelihood of back surface marking and extending the service life of components by controlling voltage polarity and levels.
Implementation Method 1
a boost circuit configured to boost a voltage supplied from a reference voltage source and generates a first power supply voltage
Implementation Method 2
a collector voltage, which is an output voltage, of the second transistor is controlled by controlling an amount of base current of the first transistor
Implementation Method 3
a voltage source connected to another end of the resistance element, the voltage source being for generating a second power supply voltage with a polarity opposite to a polarity of the first power supply voltage
Data Source
AI summary
A power supply apparatus generates an output voltage. A boost circuit boosts a voltage supplied from a reference voltage source and generates a first power supply voltage. A processor controls switching the boost circuit on and off. A first transistor is connected to the first power supply voltage. A second transistor is connected to a collector of the first transistor. A resistance element is connected to a collector of the second transistor. A voltage source is connected to the resistance element and generates a second power supply voltage. A collector voltage, which is an output voltage, of the second transistor is controlled by controlling an amount of base current of the first transistor.